Baked in Britain, the millionth Raspberry Pi

For British computing this is quite a day. The Raspberry Pi Foundation has announced that a million of the tiny cheap computers aimed at transforming education have now been made in the UK.

When the Pi was launched in February last year, the device was made in China. But a few months on, production was brought home to Sony's Pencoed factory in South Wales.

When I visited on Monday, Gareth Jones, whose job it is to win new business for the factory, told me he got in touch with the Raspberry Pi founder Eben Upton after seeing the BBC's coverage of the launch.

At first neither he nor Upton thought it would be possible to make the sums add up and produce the Pi at a price to compete with China. But then they thought about the cost of delivering from China, of having someone based there to oversee manufacturing and the quality control issues the project was already encountering. With some investment by Sony in machinery which automated a key part of the process, they decided it could work - and within a couple of months Pi production was up and running.

Since then, they've been churning out as many as 12,000 a day, and showing that manufacturing can still work in the UK.

The Pi has been exported around the world and looks set to become the best-selling British computer since the 1980s - though as it retails at about £30, it will never earn the revenues that the likes of the ZX Spectrum and the BBC Micro achieved.

"I remember being told this was an unsaleable product," says Upton, satisfied at having proved the doubters wrong. "But we've already surpassed the sales of the BBC Micro - my childhood computer. There was a latent need for something like this."

But amid all the celebrations, there is some soul-searching. Their project may have inspired middle-aged hobbyists around the world to invent all sorts of weird and wonderful things, from a Pi-powered bear leaping out of a balloon to any number of robots, musical instruments and vehicles.

But for the Raspberry Pi Foundation that was never the aim. Their mission was to transform the way children in the UK - and then in other countries - understood and used computers. True, the Raspberry Pi has been an important part of the debate which has seen the ICT curriculum ripped up and a commitment to bring in coding for children from the age of five next September.

But there isn't an awful lot of evidence that a computer designed for children is in the hands of many at the moment. Upton admits that this is a concern - and the focus must now be on education. After a donation from Google aimed at giving 15,000 Pis to children, former ICT teacher Clive Beale was appointed to drive this mission forwards.

One of the issues is training ICT teachers - after all, the bare board Raspberry Pi looks quite intimidating to anyone whose main experience has been taking students through the intricacies of Microsoft Word rather than programming.

But before talking to Upton, we had filmed an inspiring lesson at the nearby St John's College School, to see an example of what can be done.

Dr Sam Aaron, from the Cambridge University Computing Lab, has developed a program called Sonic Pi which uses the mini computer to make music. First, to illustrate how coding worked, he got the class of 10- and 11-year-olds to stand in a row passing instructions down the line.

Then they sat in pairs typing lines of Sonic Pi code to make some arresting musical compositions. Children who had never done much more with a computer than turn it on and play Angry Birds were getting a hands-on experience of how creative the coding process could be.

But making this experience available much more widely will be a challenge.

The keenest young people will find a way to get into computers, but the majority, if presented with a Raspberry Pi for Christmas, will probably stick it in a drawer and go and turn on the XBox. Changing that mindset will involve a transformation in the way schools teach computing. The Pi is a start, but is just one ingredient in a project which could take many years and much investment.